1. Field of the Invention
This invention relates generally to the field of Integrated Services Digital Network (ISDN) Terminals or Terminal Adapters (TA) and more particularly to an ISDN terminal or terminal adapter which includes a provision for providing teleconferencing (conference call) by utilizing a daisy chain switching and summing arrangement at the terminal or terminal adapter as a conference bridge.
2. Background of the Invention
Conventional teleconference arrangements are based on a centralized conference bridge architecture. A central processor situate at the hub location of a star network performs all of the switching and mixing functions required to conduct a conference. Of course, for such a network to operate, the central processor must be able to provide such function. Since this is often out of the control of the end user and often results in a special charge, this arrangement may be disadvantageous in some networks.
Another conference arrangement is the so called "hot and holler" circuit. This arrangement is essentially a private line multi-drop analog circuit which permits one way voice broadcast. This arrangement has similar drawbacks.
With the emergence of ISDN, a 2B+D basic rate service (two B Bearer channels and a packetized D signaling channel) will eventually be widely available. The present invention provides a flexible and inexpensive alternative to more conventional techniques which has the advantage of being controlled by the users terminal or terminal adapter. For purposes of this document, the term "terminal adapter" is intended to embrace devices performing conventional terminal or terminal adapter functions as well as telephone sets, terminals and the like which have the functionality of a conventional terminal adapter, i.e. 2B+D interface and multiplexing and the like, built in even though such devices may not provide some of the functions of a conventional terminal adapter (such as conversion to RS-232 for connection to non-ISDN type equipment).